Solid-State Supercapacitors

A new type of solid state device, prepared by scientists at UCLA, may provide a better method for backing up memory information on a computer in the case of a power failure. A capacitor is an electrical component for storing electrical energy in the form of negative and positively charged opposing electrodes. Its ability to do this is measured in units of farads. So called supercapacitors are perhaps a thousand times better than ordinary capacitors by being much smaller in size and by bringing the two electrodes closer together. As a quick energy storage platform, a supercapacitor can charge or discharge in a time of mere microseconds to seconds, whereas batteries take minutes to hours. However, the energy density for batteries is much higher. Hence many believe that the ideal backup energy storage device would be a hybrid of battery and supercapacitor. To be useful in that role, however, supercapacitors must be easily made and integrated onto chips. Here’s where the UCLA model proves itself: its fabrication process is simple (a simple dielectric layer of lithium fluoride sandwiched between Au, Cu, or Al electrodes), it doesn’t need an electrolyte (many other supercapacitors are halfway toward being miniature batteries in that they need electrolytes), and it can be integrated for device applications. It features a capacitance of tens of microfarad/cm² and charging rates of 10 kHz.

Ma and Yang, Applied Physics Letters, 19 September 2005
Contact Yang Yang, UCLA, 310-825-4052, yangy@ucla.edu
Yang Yang laboratory's Web site